added scss files

chrome/common/extensions/docs/static/sass/_pillar.scss

+$panel-margin-right: 1.5em;
+
+.pillar-content {
+  h1 {
+    font-size: $h1-font-size;
+  }
+  > .g-section {
+    padding: 3em 0;
+
+    &:not(:last-of-type) {
+      border-bottom: $default-border;
+    }
+    > h2 {
+      font-size: $h2-font-size;
+      margin-bottom: 1.5em !important;
+    }
+  }
+  .article-list {
+    article {
+      position: relative;
+      overflow: hidden;
+      width: 100%;
+      padding: 1.9em;
+      background-color: $gray-light;
+      box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15), 0 0 3px rgba(0, 0, 0, 0.15);
+      line-height: 1.5em;
+      margin-bottom: $panel-margin-right;
+      &.new::after {
+        content: 'new';
+        background: #2e82c9;
+        position: absolute;
+        @include transform(rotate(45deg));
+        top: -4px;
+        right: -20px;
+        color: white;
+        font-size: 0.9em;
+        width: 60px;
+        text-align: center;
+        padding-top: 8px;
+      }
+      p {
+        font-weight: 300;
+      }
+    }
+  }
+
+#further-resources .g-content {
+  h2 {
+    &::before {
+      display: inline-block;
+      content: '';
+      background: url("../images/further-resources-icons.svg") 0 50% no-repeat;
+      width: 50px;
+      height: 43px;
+      background-size: cover;
+      margin: auto;
+      margin-bottom: 5px;
+      vertical-align: middle;
+    }
+    &.school {
+      &::before {
+        background-position: 0 50%;
+      }
+    }
+    &.chat {
+      &::before {
+        background-position: -54px 50%;
+      }
+    }
+    &.puzzle {
+      &::before {
+        background-position: -108px 50%;
+      }
+    }
+  }
+}
+
+  // Phone
+  @media only screen and (max-width: $break-small)  { 
+    > .g-section {
+      padding: 2em 0;
+    }
+  }
+
+  @media only screen and (min-width: $break-small)  { 
+    .article-list {
+      @include display-flex();
+      @include flex-wrap(wrap);
+      @include justify-content(space-between);
+      @include align-items(stretch);      
+      article {
+        @include flex(auto);
+        margin-right: $panel-margin-right;
+        width: 45%;
+        &:nth-child(2n),
+        &:last-of-type {
+          margin-right: 0;
+          //max-width: 45%;
+        }
+      }
+    }
+  } 
+  @media only screen and (min-width: $break-large) { 
+    .article-list {
+      article {
+        width: 30%;
+          &:nth-child(2n) {
+          margin-right: $panel-margin-right;
+        }
+        &:nth-child(3n),
+        &:last-of-type {
+          margin-right: 0;
+        }
+      }
+    }
+  }
+}
+
+// Layout overrides for browsers who don't support Flexbox flex wrap, namely, Firefox 25 to 28.
+// Flexbox flex wrap might get support in Firefox 29. https://bugzilla.mozilla.org/show_bug.cgi?id=702508 
+@supports (not (flex-wrap: wrap)) {
+  .pillar-content {
+    .article-list {
+      display: block;
+      article {
+        @media only screen and (min-width: $break-small)  { 
+          flex: none;
+          float: left;
+          width: 48%;
+        }
+        @media only screen and (min-width: $break-large) { 
+          width: 31.8058%;
+        }
+      }
+    }
+  }
+}  
+
+// The following CSS (and matching HTML) was modified from what's on chrome.com: https://www.google.com/intl/en/chrome/devices/features/
+.load-more-articles {
+  @include clearfix;
+  margin: 2em auto 0.3em;
+  text-align: center;
+  width: 100%;
+  a,
+  a:hover {
+    color: $black;
+    transition: opacity 0.3s ease 0s;
+  }
+}
+.nav-arrow {
+  background-size: 48px 48px;
+  background: top center no-repeat;
+  display: inline-block;
+  opacity: 0.5;
+  transition: opacity 0.3s ease 0s;
+  padding-top: 50px;
+}
+.nav-arrow:hover {
+  opacity: 1;
+}
+.down-arrow {
+  background-image: url("../images/down-arrow.png");
+}
+